Are these Reported Speech answers correct

Hi teachers,
I believe all of them are right except letter 'c'. Am I right?
a) When I asked him what he was doing there, he said it was none of my business.
b) When I asked him what he was doing there, he said "It is none of your business."
c) When I asked him what he was doing there, he said to me it was none of my business.
d) When I asked him what he was doing there, he told me it was none of my business.
e) When I asked him what he was doing there he said that to me.
f) When I asked him what he was doing there, he said it was none of my business to me.

Thanks in advance.